An experimental investigation of coherent structures in the axisymmetric mixing layer of an annular jet was carried out. The Reynolds number, based on the outer diameter of the annulus, was 2.17 X 105 The flow structures of the shear layer at several downstream stations, all within 3 outer diameter distance, were examined. Conditional sampling technique was employed to educe naturally occuring large-scale structures. Coherent vorticity and coherent Reynolds stresses were, measured. It was found that the evolution of large-scale vortical structure is completed within the distance of 2 outer diameters and that the coherent Reynlods stress increases rapidly during the evolution of large-scale structure.